Estimation & Rounding
Rounding replaces a number with a simpler one at a given place value — look one digit to the right: 5 or more rounds up, 4 or less rounds down — and estimation uses rounded numbers to approximate an answer.
Round only the final answer in multi-step problems — rounding mid-calculation compounds error. This matters clinically too, where dosage answers are typically rounded at the end, per the problem’s instructions.